I don't like to recommend particular products because it's a moving target; what might be suitable for my needs today may not be suitable for my needs tomorrow, let alone suitable for your needs in the first place.
If you read proper reviews, e.g. the virus bulletin AV reviews and NOT the reviews in computer magazines which are often written by idiots and in any case aimed at home users, you may see them mention products that perform well in certain circumstances (e.g. requirements for file server, web server and email server can be very different, how important is policy based centralised management and deployment to you?). Choose a scanner that closely matches your circumstances and trial it.
As for the other stuff, again depends on what you're trying to do. Configuration requirements for a web server or edge email server are different from those for a general LAN file server.
With firewalls, again researching your proper requirements is king but I'd be looking to protect all servers with the Windows firewall itself, and wrap the whole LAN up with a "proper" (for want of a better word) firewall solution as well.
I've had good results with a "back to back" configuration with something like sonicwall/Fortinet on the outside perimeter and ISA/Forefront on the internal side. That doesn't mean that this config or my product choices are the right choices for you however, but it gets you started.